diff --git a/BaseLib/ConfigTree-impl.h b/BaseLib/ConfigTree-impl.h
index bb391cd4c2dccbb13bbdc8c05047b575676696c1..87ddab369adb363b933ea5b660af5425fdd7a8a4 100644
--- a/BaseLib/ConfigTree-impl.h
+++ b/BaseLib/ConfigTree-impl.h
@@ -27,6 +27,7 @@ public:
     Iterator begin() const { return _begin; }
     Iterator end()   const { return _end; }
     std::size_t size() const { return std::distance(_begin, _end); }
+    bool empty() const { return size() == 0; }
 
 private:
     Iterator _begin;